Radioactive isotopes Select one: a. have an excess number of electrons. b. behave the same chemically, physically, and biologically as other isotopes. c. have an excess number of neutrons. d. are produced when substances are exposed to radiation. e. are electrically unbalanced.

c. have an excess number of neutrons

Explanation:

A radioactive isotope is defined as any species of the same chemical element with unstable nuclei that emit radiation (alpha, beta, gamma) in order to dissipate its excess energy.

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